LAFAYETTE, Ind. (AP) — The National Weather Service is investigating why some northwestern Indiana residents received alerts Tuesday about a tornado warning even though the day was sunny and cold with no severe weather in sight.

Residents received alerts on their phones, saw warnings on their televisions or heard radio warnings of a tornado. They even went to Tippecanoe County Sheriff Tracy Brown, who got the alerts on his cellphone.

“I received two alerts. One said there was a tornado warning until 3 p.m.; the other said 3:15 p.m. and to take shelter now,” Brown told the Journal & Courier.

On closer inspection, he discovered those alerts were dated from 107 days ago, or about the time of the Nov. 17 tornado outbreak across Indiana.

The National Weather Service said that stations in Indianapolis, Chicago and Fort Wayne, were not responsible for the alerts even though the end of the alert read “-NWS.”

Weather Service meteorologist Gino Izzi said a tornado warning test was issued Tuesday for Illinois, but that alert clearly stated that it was a test and did not affect Indiana. He the weather service is investigating Tuesday’s tornado warning incident.

“Those higher up are investigating,” he added.

Tippecanoe Emergency Management Agency Director Smokey Anderson said he and his team don’t know which agency sent the alert, but he heard the warning early on Tuesday.

“It’s important enough that we don’t want people thinking we don’t know what we are doing and telling them to take shelter when it is sunny and 20 degrees,” Anderson said.